This thesis focuses on the analysis of Bardeen-Cooper-Schrieffer (BCS)
to Bose-Einstein condensation (BEC) evolution in ultracold superfluid
Fermi gases when the interaction between atoms is varied. The tuning of
attractive interactions permits the ground state of the system to evolve from a weak
fermion attraction BCS limit of loosely bound and largely overlapping Cooper pairs
to a strong fermion attraction limit of tightly bound small bosonic molecules
which undergo BEC.
This evolution is accompanied by anomalous behavior of many superfluid
properties, and reveals several quantum phase transitions.
This thesis has two parts:
In the first part, I analyze zero and nonzero orbital angular momentum
pairing effects, and show that a quantum phase transition occurs for
nonzero angular momentum pairing, unlike the $s$-wave case where the BCS
to BEC evolution is just a crossover.
In the second part, I analyze two-species fermion mixtures with mass and
population imbalance in continuum, trap and lattice models. In contrast with
the crossover physics found in the mass and population balanced mixtures,
I demonstrate the existence of phase transitions between normal and
superfluid phases, as well as phase separation between superfluid (paired)
and normal (excess) fermions in imbalanced mixtures as a function of scattering
parameter and mass and population imbalance.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/16326 |
| Date | 29 June 2007 |
| Creators | Iskin, Menderes |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Dissertation |
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